Amberlite IR-120：一种可重复利用的微波辅助条件下胺类化合物与甲酸N-甲酰化反应的催化剂

 A rapid and practical green route for the N-formylation of amines with formic acid using Amberlite IR-120 as a catalyst is described. This method provides an efficient and much improved modification over the reported methods in terms of yield, reaction time, and work-up procedure. A wide variety of substituents is tolerated, which is not the case for existing procedures.     

PROPERTIES OF SILK FIBROIN/POLY(ETHYLENE GLYCOL)400 BLEND FILMS

The blend film of silk fibroin (SF) and poly(ethylene glycol)400 (PEG400) with a blend ratio of 2/1 (wt/wt) wasprepared simply by dropping a little PEG400 into the SF solution and then casting the mixed aqueous solution at 50℃. Theresulting film exhibited much better mechanical properties in the dry and wet state than SF itself, owing to theconformational change of SF in the blends from the random coil to the β-sheet structure and intermolecular hydrogen bondformation between SF and PEG400. Thermogravimetric analysis showed that the initial thermal decomposition temperatureof the blend film was 170℃, which was 80℃ lower than that of SF (250℃) and 20℃ higher than that of PEG400 (150℃),and indicated a Strong interaction between two components of the blend. No crystalline peaks were observed in the X-raydiffraction curve of the blend film. Cell culture test showed that SF/PEG400 was a suitable substrate for the growth of humanumbilical vein endothelial cells (HUVEC).     

微波固相反应制备CdS纳米粒子

硫化镉是一种重要的半导体材料,在太阳能转化、非线形光学、光电子化学电池和光催化方面具有广泛的应用[1,2]。近十年以来,人们已经使用了许多的方法来制备纳米硫化镉[3~7]。由于微波能同时促进吸热反应和放热反应,对化学反应具有催化作用,可降低反应的温度,从而为化学反应创造     

Solid Phase Extraction of Trace Metals in Seawater Using Morpholine Dithiocarbamate‐Loaded Amberlite XAD‐4 and Determination by ICP‐AES

Abstract

Application of morpholine dithiocarbamate (MDTC) coated Amberlite XAD‐4, for preconcentration of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II) by solid phase extraction and determination by inductively coupled plasma (ICP) atomic emission spectrometry (AES) was studied. The optimum pH values for quantitative sorption of Cu(II), Cd(II), Zn(II), Pb(II), Ni(II), and Mn(II) were 6.5–8.0, 7.0–8.5, 6.0–8.5, 6.5–8.5, 7.5–9.0, and 8.0–8.5, respectively. The metals were desorbed with 2 mol L^?1. The t_1/2 values for sorption of metal ions were 2.6, 2.9, 2.5, 2.6, 3.0, and 3.8 min respectively for Cu(II), Cd(II), Zn(II), Pb(II), Ni(II) and Mn(II). The effect of diverse ions on the determination of the previously named metals was studied. Simultaneous enrichment of the six metals was accomplished, and the method was applied for use in the determination of trace metal ions in seawater samples.     

Speciation analysis of inorganic Sb(III) and Sb(V) ions by using mini column filled with Amberlite XAD-8 resin

The speciation of inorganic Sb(III) and Sb(V) ions in aqueous solution was studied. The adsorption behavior of Sb(III) and Sb(V) ions were investigated as iodo and ammonium pyrollidine dithiocarbamate (APDC) complexes on a column filled with Amberlite XAD-8 resin. Sb(III) and Sb(V) ions were recovered quantitatively and simultaneously from a solution containing 0.8 M NaI and 0.2 M H₂SO₄ by the XAD-8 column. Sb(III) ions were also adsorbed quantitatively as an APDC complex, but the recovery of the Sb(V)-APDC complex was found to be <10% at pH 5. According to these data, the concentrations of total antimony as Sb(III)+Sb(V) ions and Sb(III) ion were determined with XAD-8/NaI+H₂SO₄ and XAD-8/APDC systems, respectively. The Sb(V) ion concentration was calculated by subtracting the Sb(III) concentration found with XAD-8/APDC system from the total antimony concentration found with XAD-8/NaI+H₂SO₄ system. The developed method was applied to determine Sb(III) and Sb(V) ions in samples of artificial seawater and wastewater.     

流动注射化学发光测定甲基对硫磷

首次研究了农药甲基对硫磷在碱性介质中（ｐＨ：１１．５～１２．０）与鲁米诺和过氧化氢产生化学发光的行为及反应机理,并发现水溶性高分子聚乙二醇对该反应具有显著的增效作用,据此建立了流动注射化学发光测定甲基对硫磷的新方法。甲基对硫磷的浓度在 ５×１０－８～１．０ ×１０－５ｇ／ｍＬ范围内与化学发光强度呈良好的线性关系;检出限为 ２×１０－８ｇ／ｍＬ;对 １．０×１０－６ｇ／ｍＬ甲基对硫磷进行了１１次平行测定,相对标准偏差小于４％;标准加入回收率为８３％～９４％。该法应用于谷物中农药残余量的测定,结果满意。     

Multicomponent reactions in PEG-400: ruthenium-catalyzed synthesis of substituted pyrroles

An efficient and eco-friendly method for the synthesis of substituted pyrroles has been developed via ruthenium-catalyzed multicomponent reaction of ketone, amine, and ethylene glycol in PEG-400 as solvent medium without using any external ligand. The catalytic system and solvent can be recycled with the same, as well as different, ketones with minimum loss of Ru-catalyst activity.     

PEG-400 promoted Pd(OAc)2/DABCO-catalyzed cross-coupling reactions in aqueous media

PEG-400 [poly(ethylene glycol-400)] was found to improve the Pd(OAc)₂/DABCO-catalyzed aqueous Suzuki-Miyaura and Stille cross-coupling reactions. In the presence of Pd(OAc)₂, DABCO, and PEG-400, a variety of aryl halides were coupled with arylboronic acids or organotin compounds efficiently to afford the corresponding cross-coupled products in moderate to excellent yields. The turnover numbers was up to 900,000 for the Suzuki-Miyaura reaction and up to 9800 for the Stille reaction. The catalyst system was also effective for Heck and Sonogashira cross-coupling reactions to some extent.     

镧对SS400钢组织及力学性能的影响

研究了镧对SS400钢常温及低温力学性能的影响。结果表明,SS400钢的强度、塑性、冲击韧性以及硬度随镧含量的增加能够得到明显改善,但当镧加入量过大时,会造成SS400钢的强度、塑性、冲击韧性下降。将镧含量控制在0.016%左右能够有效提高其各项力学性能。镧提高SS400钢的力学性能,是其对钢净化钢液、变质夹杂、微合金化综合作用的结果。     

L-proline catalyzed multicomponent domino reaction in polyethyleneglycol-400 for regioselective synthesis of pyrazolyl-tetrahydroindazolones under microwave irradiation

A simple and convenient approach for the synthesis of pyrazolyl-tetrahydroindazolones via L-proline catalyzed three component domino reaction of arylhydrazine, dimedone and pyrazole aldehyde in polyethyleneglycol-400 (PEG-400) under microwave irradiation is described. This novel and green protocol proceeds smoothly in good to excellent yields and provides several advantages such as shorter reaction time, metal-free reaction conditions, simple work-up procedures. Also, recycling of the catalyst and solvent was observed without the loss of activity for three (03) runs.